<!-- c -->
<template>
    <!-- 商品分类导航 -->
    <div class="type-nav">
        <div class="container">
            <h2 class="all" @mouseenter="changeShow(true)" @mouseleave="changeShow(false)">全部商品分类</h2>
            <nav class="nav">
                <a href="###">服装城</a>
                <a href="###">美妆馆</a>
                <a href="###">尚品汇超市</a>
                <a href="###">全球购</a>
                <a href="###">闪购</a>
                <a href="###">团购</a>
                <a href="###">有趣</a>
                <a href="###">秒杀</a>
            </nav>
            <!-- 三级联动 -->
            <transition 
                name="animate__animated animate__bounce" 
                enter-active-class="animate__fadein"
                leave-active-class="animate__fadeOut"  :duration="{ enter:500, leave:100 }">
                <div class="sort" v-show="show" @mouseenter="changeShow(true)" @mouseleave="changeShow(false)">
                    <!-- 这里的路由跳转用到了事件委派！！ -->
                    <div class="all-sort-list2" @click="goSearch">
                        <div class="item" v-for="(c1, index) in categoryList" :key="c1.categoryId"
                            :class="{ cur: currentIndex == index }">
                            <!-- 鼠标移入一级分类实现背景天蓝色：动态绑定class样式 -->
                            <h3 @mouseenter="changeIndex(index)" @mouseleave="changeIndex(-1)">
                                <a :data-categoryName="c1.categoryName" :data-category1Id="c1.categoryId">{{
                                    c1.categoryName
                                }}</a>
                            </h3>
                            <!-- 二级、三级分类 -->
                            <div class="item-list clearfix">
                                <div class="subitem" v-for="(c2, index) in c1.categoryChild" :key="c2.categoryId">
                                    <dl class="fore">
                                        <dt>
                                            <a :data-categoryName="c2.categoryName" :data-category2Id="c2.categoryId">{{
                                                c2.categoryName
                                            }}</a>
                                        </dt>
                                        <dd>
                                            <em v-for="(c3, index) in c2.categoryChild" :key="c3.categoryId">
                                                <a :data-categoryName="c3.categoryName"
                                                    :data-category3Id="c3.categoryId">{{
                                                        c3.categoryName
                                                    }}</a>
                                            </em>
                                        </dd>
                                    </dl>
                                </div>
                            </div>
                        </div>

                    </div>
                </div>
            </transition>

        </div>
    </div>
</template>

<script>
import { mapState } from 'vuex';
import throttle from 'lodash/throttle';  //lodash按需引入
import debounce from 'lodash/debounce';
import 'animate.css'

export default {
    name: "TypeNav",
    data() {
        return {
            currentIndex: -1,  //鼠标移动到的一级分类，实现天蓝色背景
            show: true,
        }
    },
    computed: {
        ...mapState('home', ['categoryList'])
    },
    methods: {
        changeIndex: throttle(function (index) {
            this.currentIndex = index
        }, 20),

        //编程式导航+事件委派！！！！
        goSearch(event) {
            let element = event.target
            //节点有一个dataset属性，可以获取节点的 自定义属性:属性值，【注意会把key值都变成小写！！！】
            // console.log(element.dataset)
            let { categoryname, category1id, category2id, category3id } = element.dataset// 【注意会把key值都变成小写！！！】

            if (categoryname) {  //判断是否是a标签
                let query = { categoryName: categoryname }  //query参数

                if (category1id) {
                    query.category1Id = category1id
                } else if (category2id) {
                    query.category2Id = category2id
                } else {
                    query.category3Id = category3id
                }

                this.$router.push({ //路由跳转
                    name: 'search',
                    query,
                    params: this.$route.params  //保留参数
                })
            }
        },

        changeShow: debounce(function (tf) {  //防抖，避免离开【全部商品分类】的时候执行动画
            if (tf == false && this.$route.path == '/home') {  //如果是移除事件
                return
            }
            this.show = tf
        }, 1)

    },

    mounted() {
        if (this.$route.path != '/home') {  //如果不是Home路由，将TypeNav隐藏
            this.show = false
        }
    },

}
</script>

<style lang="less" scoped>
.type-nav {
    border-bottom: 2px solid #e1251b;

    .container {
        width: 1200px;
        margin: 0 auto;
        display: flex;
        position: relative;
        .all {
            width: 210px;
            height: 45px;
            background-color: #e1251b;
            line-height: 45px;
            text-align: center;
            color: #fff;
            font-size: 14px;
            font-weight: bold;
        }

        .nav {
            a {
                height: 45px;
                margin: 0 22px;
                line-height: 45px;
                font-size: 16px;
                color: #333;
            }
        }

        .sort {
            position: absolute;
            left: 0;
            top: 45px;
            width: 210px;
            height: 461px;
            background: #fafafa;
            z-index: 999;

            .all-sort-list2 {
                .cur {
                    //实现一级分类鼠标移动天蓝色背景
                    background-color: skyblue;
                }

                .item {
                    h3 {
                        // line-height: 30px;  //修改样式  
                        line-height: 27.3px;
                        font-size: 14px;
                        font-weight: 400;
                        overflow: hidden;
                        padding: 0 20px;
                        margin: 0;

                        a {
                            color: #333;
                        }
                    }

                    .item-list {
                        display: none;
                        position: absolute;
                        width: 734px;
                        min-height: 460px;
                        background: #f7f7f7;
                        left: 210px;
                        border: 1px solid #ddd;
                        top: 0;
                        z-index: 9999 !important;

                        .subitem {
                            float: left;
                            width: 650px;
                            padding: 0 4px 0 8px;

                            dl {
                                border-top: 1px solid #eee;
                                padding: 6px 0;
                                overflow: hidden;
                                zoom: 1;

                                &.fore {
                                    border-top: 0;
                                }

                                dt {
                                    float: left;
                                    width: 54px;
                                    line-height: 22px;
                                    text-align: right;
                                    padding: 3px 6px 0 0;
                                    font-weight: 700;
                                }

                                dd {
                                    float: left;
                                    // width: 415px;  //修改样式
                                    padding: 3px 0 0;
                                    overflow: hidden;

                                    em {
                                        float: left;
                                        height: 14px;
                                        line-height: 14px;
                                        padding: 0 8px;
                                        margin-top: 5px;
                                        border-left: 1px solid #ccc;
                                    }
                                }
                            }
                        }

                    }

                    &:hover {
                        .item-list {
                            display: block;
                        }
                    }
                }
            }
        }
    }
}
</style>
